Fatty Acid Synthase (FAS) is a critical enzyme for endogenous lipogenesis and plays an important role in the modulation of key intermediates of lipid and carbohydrate cellular metabolism. FAS is highly expressed in the tissues with high metabolic activity (for example liver, adipose tissue and brain) and there are good reasons to believe that a FAS inhibitor would cause beneficial metabolic effects in peripheral tissues. In addition, inhibition of FAS in the hypothalamus may result in reduced food intake. The non-specific irreversible FAS inhibitors cerulenin and C-75 have been reported in the literature to decrease brain levels of orexigenic neuropeptides and to decrease food intake.
FAS is also highly expressed in human sebocytes, the lipid producing cells of the sebaceous glands. Acne is the most common disorder involving the sebaceous gland. The pathogenesis of acne involves lipid (over)production by the sebaceous gland and it has been reported that inhibitors of mammalian FAS inhibit the production of sebum in sebocytes (US 2005/0053631). Acne cannot occur without sebum lipids. There is an unmet medical need in the treatment of acne for agents that reduce sebum production.
Since fatty acid synthesis in bacteria is essential for cell survival, bacterial FAS (type II synthase) has emerged as a potential target for antibacterial therapy. Unlike in most other prokaryotes, fatty acid synthase activity in mycobacteria is carried out by a single high-molecular-weight, multifunctional peptide chain (type I synthase) related to mammalian FAS. Mycobacterial type I FAS has been described as a potential target for antimycobacterial therapy, e.g. the treatment of tuberculosis. With one-third of the world's population being infected with the tuberculosis bacillus, and multidrug-resistant strains of Mycobacterium tuberculosis developing, there is a high medical need for novel tuberculosis therapies. (Silvana C. Ngo, et al.: Inhibition of isolated Mycobacterium tuberculosis Fatty Acid Synthase I by Pyrazinamide Analogs; Antimicrobial agents and Chemotherapy 51,7 (2007) 2430-2435).
Recently, microdomains of organelle membranes rich in sphingomyelin and cholesterol (called “lipid rafts”) have been considered to act as a scaffold for the hepatitis C virus (HCV) replication complex (F. Amemiya, et al.: Targeting Lipid Metabolism in the Treatment of Hepatitis C Virus Infection. The Journal of Infectious Diseases 197 (2008) 361-70). Consequently, alterations of membrane lipid composition and/or distribution may influence viral replication. Indeed, agents related to lipid metabolism like polyunsaturated fatty acids or HMG-CoA reductase inhibitors (statins) have been shown to affect the replication of genotype 1 HCV (dto). These agents may attenuate HCV replication through the destruction of lipid rafts, according to their pharmacological actions. An alternative molecular mechanism possibly responsible for the inhibition of HCV replication is via altering localization of host proteins through alterations in lipid anchoring (S. M. Sagan, et al.: The influence of cholesterol and lipid metabolism on host cell structure and hepatitis C virus replication. Biochem. Cell Biol. 84 (2006) 67-79). Unlike polyunsaturated fatty acids, addition of saturated fatty acids or oleic acid to cultured Sfil cells promoted HCV RNA replication (S. B. Kapadia, F. V. Chisari: Hepatitis C virus RNA replication is regulated by host geranylgeranylation and fatty acids. PNAS 102 (2005) 2561-66). In line with this, it has been reported that expression of fatty acid synthase was increased in a human hepatoma cell line upon HCV infection (W. Yang, et al.: Fatty acid synthase is up-regulated during hepatitis C virus infection and regulates hepatitis C virus entry. Hepatology 48,5 (2008) 1396-1403). Furthermore, inhibition of fatty acid biosynthesis by TOFA (an inhibitor of acetyl-CoA carboxylase) or inhibitors of fatty acid synthase (cerulenin, C75), led to decreased HCV production (dto).
The effect of fatty acid synthase (FAS) activity on viral replication or infection appears not to be restricted to HCV, but has also been reported for HIV (D. H. Nguyen, D. D. Taub: Targeting Lipids to Prevent HIV infection. Molecular Interventions 4,6 (2004) 318-320), Poliovirus (R. Guinea, L. Carrasco: Effects of Fatty Acids on Lipid
Synthesis and Viral RNA Replication in Poliovirus-Infected Cells. Virology 185 (1991) 473-476), Epstein-Barr virus (Y. Li., et al.: Fatty acid synthase expression is induced by the Epstein-Barr virus immediate-early protein BRLF1 and is required for lytic viral gene expression. Journal of Virology 78,8 (2004) 4197-4206), human papilloma virus (L. Louw, et al.: HPV-induced recurrent laryngeal papillomatosis: fatty acid role-players. Asia Pac J Clin Nutr 17 (S1) (2008) 208-211), coxsackievirus B3 (A. Rassmann, et al.: The human fatty acid synthase: A new therapeutic target for coxsackievirus B3-induced diseases? Antiviral Research 76 (2007) 150-158), Rous sarcoma virus (H. Goldfine, et al.: Effects of inhibitors of lipid synthesis on the replication of Rous Sarcoma Virus. A specific effect of cerulenin on the processing of major non-glycosylated viral structural proteins. Biochimica et Biophysica Acta 512 (1978) 229-240), as well as human cytomegalovirus (HCMV), and influenza A virus (J. Munger, et al.: Systems-level metabolic flux profiling identifies fatty acid synthesis as a target for antiviral therapy. Nature Biotechnology 26 (2008) 1 179-1 186).
Taken together, there is growing evidence, that activity of the host's FAS plays an important role in viral infection and viral replication, suggesting FAS as a target for antiviral therapy. The expression of FAS is strongly increased in many cancers and there is evidence that efficient fatty acid synthesis is required for tumor cell survival. Inhibition of FAS has therefore been suggested as a new direction for oncology (Expert Opin. Investig. Drugs 16,1 (2007)1817-1829).
Fatty acids have an essential role in a variety of cellular processes including building blocks for membranes, anchors for targeting membrane proteins, precursors in the synthesis of lipid second messengers and as a medium to store energy, Menendez J S and Lupu R, Fatty acid synthase and the lipogenic phenotype in cancer pathogenesis, Nature Reviews Cancer, 7: 763-777 (2007). Fatty acids can either be obtained from the diet or can be synthesized de novo from carbohydrate precursors. The biosynthesis of the latter is catalyzed by the multi-functional homodimeric FAS. FAS synthesizes long chain fatty acids by using acetyl-CoA as a primer and Malonyl Co-A as a 2 carbon donor, and NADPH as a reducing equivalents (Wakil S J, Lipids, Structure and function of animal fatty acid synthase, 39: 1045-1053 (2004), Asturias F J et al., Structure and molecular organization of mammalian fatty acid synthase, Nature Struct. Mol. Biol. 12:225-232 (2005), Maier T, et al., Architecture of Mammalian Fatty Acid Synthase at 4.5 A Resolution, Science 311 : 1258-1262 (2006).
De novo fatty acid synthesis is active during embryogenesis and in fetal lungs where fatty acids are used for the production of lung surfactant. In adults, most normal human tissues preferentially acquire fatty acids from the diet. Therefore, the level of de novo lipogensis and expression of liopogenic enzymes is low, Weiss L, et al, Fatty-acid biosynthesis in man, a pathway of minor importance. Purification, optimal assay conditions, and organ distribution of fatty-acid synthase. Biological Chemistry Hoppe-Seyler 367(9):905-912 (1986). In contrast, many tumors have high rates of de novo fatty acid synthesis Medes G, et al, Metabolism of Neoplastic Tissue. IV. A Study of Lipid Synthesis in Neoplastic Tissue Slices in Vitro, Can Res, 13:27-29, (1953). FAS has now been shown to be overexpressed in numerous cancer types including prostate, ovary, colon, endometrium lung, bladder, stomach and kidney Kuhajda F P, Fatty-acid synthase and human cancer: new perspectives on its role in tumor biology, Nutrition; 16:202-208 (2000). This differential expression and function of FAS in tumors and normal cells provide an approach for cancer therapy with the potential of a substantial therapeutic window.
Pharmacological and small interference RNA mediated inhibition of FAS has demonstrated a preferential inhibition of cancer cell proliferation. Additionally these inhibitors induce apoptosis in cancers cells in vitro and retard growth in human tumors in murine xenograft models in vivo, Menendez J S and Lupu R, Nature Reviews Cancer, 7: 763-777 (2007). Based upon these findings, FAS is considered a major potential target of antineoplastic intervention.
The invention had the object of finding novel compounds having valuable properties, in particular those which can be used for the preparation of medicaments.
It has been found that the compounds according to the invention and salts thereof have very valuable pharmacological properties while being well tolerated.
The present invention specifically relates to compounds of the formula I which inhibit FASN, to compositions which comprise these compounds, and to processes for the use thereof for the treatment of FASN-induced diseases and complaints.
The compounds of the formula I can furthermore be used for the isolation and investigation of the activity or expression of FASN. In addition, they are particularly suitable for use in diagnostic methods for diseases in connection with unregulated or disturbed FASN activity.
The host or patient can belong to any mammalian species, for example a primate species, particularly humans; rodents, including mice, rats and hamsters; rabbits; horses, cows, dogs, cats, etc. Animal models are of interest for experimental investigations, providing a model for treatment of human disease.
The susceptibility of a particular cell to treatment with the compounds according to the invention can be determined by in vitro tests. Typically, a culture of the cell is combined with a compound according to the invention at various concentrations for a period of time which is sufficient to allow active agents such as anti IgM to induce a cellular response such as expression of a surface marker, usually between about one hour and one week. In vitro testing can be carried out using cultivated cells from blood or from a biopsy sample. The amount of surface marker expressed is assessed by flow cytometry using specific antibodies recognising the marker.
The dose varies depending on the specific compound used, the specific disease, the patient status, etc. A therapeutic dose is typically sufficient considerably to reduce the undesired cell population in the target tissue while the viability of the patient is maintained. The treatment is generally continued until a considerable reduction has occurred, for example an at least about 50% reduction in the cell burden, and may be continued until essentially no more undesired cells are detected in the body.